Fix SQ4 AVX-512 implementation (zilliztech#506)

Signed-off-by: Alexandr Guzhva <alexanderguzhva@gmail.com>
alexanderguzhva · Apr 17, 2024 · 79d00e3 · 79d00e3
1 parent 4f88afc
commit 79d00e3
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/thirdparty/faiss/faiss/impl/ScalarQuantizerCodec_avx512.h b/thirdparty/faiss/faiss/impl/ScalarQuantizerCodec_avx512.h
@@ -53,7 +53,7 @@ struct Codec4bit_avx512 : public Codec4bit_avx {
         __m128i c16 =
                 _mm_unpacklo_epi8(_mm_set1_epi64x(c8ev), _mm_set1_epi64x(c8od));
         __m256i c8lo = _mm256_cvtepu8_epi32(c16);
-        __m256i c8hi = _mm256_cvtepu8_epi32(_mm_srli_si128(c16, 4));
+        __m256i c8hi = _mm256_cvtepu8_epi32(_mm_srli_si128(c16, 8));
         __m512i i16 = _mm512_castsi256_si512(c8lo);
         i16 = _mm512_inserti32x8(i16, c8hi, 1);
         __m512 f16 = _mm512_cvtepi32_ps(i16);